Idiosyncrasy.

Walk this way.

Dear Word Detective: What is the history of the word “idiosyncrasy” — how did it come about? — Bear Mistel.

That’s a darn good question. By the way, you have a very cool name. I knew a guy named Tiger once, and years ago I worked with a fellow called Duck (although I’m not sure he knew we called him Duck). Of course, during the 1960s, everyone knew somebody named Raven Rainbow Moonwolf or the like, but most of those people have long since gone back to being Larry or Cynthia.

In a general sense, we use “idiosyncrasy” today to mean the particular likes and dislikes of a person or group, the quirks, tastes, preferences, prejudices and just plain weirdnesses that make up the human personality. An “idiosyncrasy” in this sense is, by definition, at least somewhat uncommon among the members of one’s peer group. Here in rural Ohio, for instance, most people would consider my affection for borscht (beet soup) an idiosyncrasy, but borscht is very popular in New York City. (Conversely, many New Yorkers would regard my Ohio neighbors’ devotion to sausage gravy as a symptom of insanity.) A personal “idiosyncrasy” can be nearly anything, but often involves an uncommon “fussiness” about something. A strong preference that one’s meat not touch one’s potatoes, for example, is a classic idiosyncrasy. In fact, food idiosyncrasies are mainstays of both family legends and folklore. I still remember a bit of doggerel I read when I was about ten that ran “I eat my peas with honey; I’ve done it all my life; It does taste kind of funny; But it keeps them on the knife.”

When “idiosyncrasy” first came into use in English in the 17th century, however, it was as a medical term meaning “the physical constitution of an individual,” the medically-relevant characteristics of a particular patient. This sense is now only used to mean a patient’s hypersensitivity to a drug or other treatment, e.g., an allergy to penicillin.

The roots of “idiosyncrasy” are Greek, a combination of “idios,” meaning “one’s own, individual,” and “synkrasis,” meaning “mixture, temperament.” Interestingly, that “idios” also underlies two other common English words. An “idiom” (from the Greek “idioma”) is a particularity, usually a term or phrase, in the speech or language of a group or inhabitants of a certain locale. The signature characteristic of an idiom is that merely grasping the words that make it up doesn’t give you its real meaning — the idiom “that dog won’t hunt” isn’t really about either dogs or hunting. It helps to have spent time in the American South to know that it means “that will not do what you expect it to do.”

“Idios” is also the root of our modern word “idiot.” The Greek “idiotes” was a private man, as opposed to a public figure, but “idiot” in English came to mean “uneducated common man,” and, eventually, “a stupid person.”